Check out example codes for "rails command line". It will help you in understanding the concepts better.

Code Example 1

rails new app_name #creates a new rails application
rails server or rails s #runs the rails server
rails generate or rails g #gives a list of available generators 
rails console or rails c #opens up the rails console that allows you 
						 # to interact with your rails application
rails destroy or rails d #allows you to destroy what was previously created
# ex: rails g model Oops - creates
# ex: rails d model Oops - deletes what was created
rails about #gives info about your ruby application including the version, etc.
rails -T #opens up the rails tasks list to give you info on what you can run.
rails db: #most common command, allows you to run create or migrate
#ex: rails db:migrate - runs the migration
#ex: rails db:seed - seeds your DB from what was added in your seed file

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